oil in my coolant

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Joined
Feb 25, 2006
Threads
78
Messages
280
Location
Leadville, CO
There's oil in my coolant but no coolant in my oil. Seems like the oil cooler, or worse, the head. Did anyone solve this problem with a new oil cooler? Besides the head, it seems like the only place for oil to escape being under more pressure, perhaps, than the coolant. After a few thousand miles I poured a quart of oil out of the overflow.
 
Definitly oil. I'm considering a recovery filter system so I can just send it back, ha ha.
 
I have had this prob for some time.Mine is a very small amount.Had my oil cooler pressure tested and all is well.(eng oil cooler mine has no transmission cooler)Is it possible the PS pump can leak into the coolling system? I think not ,but it is the only thing i top up between services.:crybaby:

Here comes the LEXUS V8
 
There's oil in my coolant but no coolant in my oil.

What engine are we talking about here? Your sig line is showing "78fj40 & 84fj60 & 50 chevy" but no 80-Series.

-B-
 
well, getting oil to migrate into a pressurized cooling system takes some effort. I'd have to think it's getting there from a pressurized oil galley or passageway. I don't know the entire structure of the block but we have had a few crack at one of the freeze plugs. If that crack managed to span between the two then oil would get pumped into the coolant.

Look around on both sides of the block at the freeze plugs for coolant leakage.
 
It's a '97 lx450. I need to update the sig. The tranny fluid is fine by the way, so nothing suspicious there. Can you pressure test the oil cooler without removing it? I suspect something internal but I need to rule out the oil cooler first.
 
Another thought, the coolant system is not pressurized when it's cold. Perhaps that is when the oil migrates the most.
 
I found a new oil cooler on specter for 450, ouch. Help. Where else should I look?
 
Ripple

99.9% of the time the eng oil cooler or gaskets are the prob.
But in my case not.I would think when you shut the engine of the oil pressure is 0 and water pressure still up so why no water in the eng oil? Let us know what you find.
 
So I replaced the oil cooler gaskets and I am now flushing the system out to remove the oil and, hopefully, determine if I fixed it. There was nothing visibly wrong with the oil cooler and with some improvised air pressure test, no oil leaking from the body of the cooler. I'm now removing the top radiator hose, running the motor, and adding water to the radiator. The oil has killed my thermo, so the flush starts immediately. Is there anything that I could add to the flush to remove the oil debree/film which exists everywhere inside the cooling system? At 10,000 ft, I only have a month where I can comfortably run water only in the system. Once I find the problem, all hoses and thermo get replaced. The plastic radiator is holding up "ok" so far considering the damage that the oil may be causing.
 
There are detergent flushes for the cooling system as opposed to the acid cleaning type for normal deposits. You might flush it a couple times with the detergent as it sounds like you have a lot of oil that was in the system. Don't drive around with only water in the system more than a few hours. Your block is cast iron and needs the anti rust agents in the coolant.

Hope the gasket was the problem.

DougM
 
After pulling the head, it looks like the head gasket is not the culprit. Perhaps there are cracks in the head or block. Is there any chance that coolant and oil could mix in the radiator. As I was pulling everything out I found the 2 oil lines connected to the base of the radiator. I've never heard of this being a problem with anyone, but I'll be damned if there aren't oil lines running into the radiator. Sure seems possible at this point.
 
Is there any chance that coolant and oil could mix in the radiator. As I was pulling everything out I found the 2 oil lines connected to the base of the radiator. I've never heard of this being a problem with anyone, but I'll be damned if there aren't oil lines running into the radiator. Sure seems possible at this point.

Those are the lines for your transmission (there is a cooler in the bottom of the radiator). Could you have confused ATF fluid for oil?
 
oil cooler inside radiator.

" I've never heard of this being a problem with anyone,"

My oil cooler inside the radiator was leaking atf fluid into the radiator and water into the transmission of my 96´

had to do a complete flush on both systems and replace the radiator, problem fixed.


link to my tread on this.

https://forum.ih8mud.com/80-series-tech/249857-transmission-oil-radiator-can.html

cheers.
 
Last edited:
Thanks, but it's definitely oil. Guess I was just getting overly optimistic once again. Good news is a buddy is going to let me use part of his shop to now complete the motor swap once I find another motor. It's snowing and I am garageless.
 

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